package com.wsjj.yjh;

import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

public class TransKeyBy {
    public static void main(String[] args) throws Exception {
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
        DataStreamSource<WaterSensor> source = env.fromElements(
                new WaterSensor("sensor_1", 1L, 1),
                new WaterSensor("sensor_1", 2L, 2),
                new WaterSensor("sensor_2", 2L, 2),
                new WaterSensor("sensor_3", 3L, 3)
        );
// 方式一：使用匿名类实现KeySelector
        source.keyBy(new KeySelector<WaterSensor, String>() {
            @Override
            public String getKey(WaterSensor value) throws Exception {
                return value.id;
            }
        }).print();
// 方式二：使用Lambda表达式
        source.keyBy(value -> value.id).print();
        env.execute();
    }
}
